Good example of passing data through a 5 promise chain.

chainSimple.js

@@ -0,0 +1,36 @@
+let a = function(x) {
+    console.log(x + 'a');
+    return new Promise (function(resolve, tin){
+        x += " mercury";
+        resolve(x);
+    })
+}
+
+let b = function(x) {
+    console.log(x + 'b');
+    return new Promise (function(resolve, tin){
+        x += " venus";
+        resolve(x);
+    })
+}
+let c = function(x) {
+    console.log(x + 'c');
+    return new Promise (function(resolve, tin){
+        x += " earth";
+        resolve(x);
+    })
+}
+let d = function(x) {
+    console.log(x + 'd');
+    return new Promise (function(resolve, tin){
+        x += " mars";
+        resolve(x);
+    })
+}
+
+
+a('Stoughton ')
+.then(b)
+.then(c)
+.then(d)
+.then((x) => {console.log("big payoff is: "); console.log(x);  })